Research On Four-dimensional Path Planning For Heterogeneous Aircraft Swarm

Heterogeneous aircraft swarm flexibly configure different types of aircrafts with different capabilities and payloads and generate flexible and changeable combat capabilities in order to better adapt to complex battlefield environments.The Heterogeneous swarm cooperative mission has strict flight time limits on the aircrafts.In order to improve the security and reliability in executing complex mission,the space-time four-dimensional(4D)cooperative flight path planning problem has become a urgently technical problem.The space-time four-dimensional coordinated flight path planning is constrained by complex environment under intense confrontation conditions,heterogeneous aircraft capability constraints,strong time constraints,multi-aircraft space-time conflicts etc.,and it is difficult to achieve efficient paths by a single method.Based on the problems above,this paper conducts a systematic and in-depth study on the cooperative planning modeling,four-dimensional trajectory planning algorithm,spatial conflict judgment and resolution methods,time coordination and adjustment strategies in the space-time four-dimensional planning of heterogeneous aircrafts.The main contents of this paper are as follows:1.According to the constraints of complex environment and aircraft maneuverability,a space-time four-dimensional planning model for heterogeneous aircrafts is established.Based on the integration of the SRTM(Shuttle Radar Topography Mission)data and various threats,a planning environment model is established.The maneuvering capability constraint model of fixed-wing UAV including turning angular velocity,climbing rate and flight time is established.The time cooperation,space cooperation constraint model and cooperation planning cost model of swarm aircraft are established.2.According to the requirement of four-dimensional path planning for a single UAV,the path planning and smoothing method and the velocity planning method are proposed.Based on the time-dimension-added ant colony algorithm,the four-dimensional path is planned.Based on 3D Dubins algorithm,the initial path is smoothed to meet the aircraft maneuvering constraints.In view of the time error caused by the sudden situation and track smoothing,two velocity planning methods with time dimension are proposed,and the applicability of these methods is analyzed.3.According to the possible space conflicts between multiple aircrafts,CDR(conflict detection and resolution)is established.Based on the framework of multi-aircraft path planning,an improved multi-ant colony collaborative route planning method is proposed.Four typical models of multi-aircraft space conflicts are established and the conflict resolution methods are proposed.The effectiveness of CDR is verified by simulation.4.Aiming at the coordination time adjustment between multiple aircrafts,a strategy of coordination adjustment for heterogeneous multiple aircrafts is proposed.Three time adjustment strategies are put forward: adjusting the takeoff time,adjusting the flight speed and adopting the flying-around scheme.The complex terrain is divided into regions to define the scope of strategy implementation.Finally,the cooperative mission simulation of three aircrafts is used to explain the cooperation method and the operation effect of the strategies.